This application claims priority of German Application No. 101 18 464 6 filed Apr. 7, 2001, the complete disclosures of which is hereby incorporated by reference.
a) Field of the Invention
The invention is directed to an electrical probe. A probe of this kind can preferably be used in ophthalmological surgery for electrosurgical cutting, ablation or coagulation of tissue.
b) Description of the Related Art
The use of electrosurgical procedures in ophthalmology is known per se and is disclosed, for example, in U.S. Pat. Nos. 6,135,998 and 5,755,716. U.S. Pat. No. 6,135,998 describes a probe in which an outer electrode is constructed coaxially around an inner wire-shaped electrode. The space between the electrodes is filled with an insulating material, e.g., also glass or fused silica.
Further, combined probes used for electrosurgical operation and laser operation are also known from general surgery (e.g., U.S. Pat. Nos. 5,011,483 and 5,509,916). In these cases, the laser light of correspondingly high-power lasers is guided in the vicinity of the ends of the electrodes of the electrosurgical probe by means of separate light-conducting fibers in order to treat the tissue with laser radiation as needed.
In operative use of an electrosurgical probe in ophthalmology, ensuring sufficient illumination of the interior of the eye and the fundus oculi is problematic. Therefore, illumination which is supplied via a second incision is often used in addition to the surgical tool. This additionally complicates performance of the operation and considerably increases stress and risk for the patient.
Therefore, it is the primary object of the invention to provide a novel probe which makes the use of the probe more economical and improves the illumination conditions at the working location of the probe.
According to the invention, this object is met in an electrosurgical probe comprising a first electrode, a second electrode arranged coaxial to the first electrode and an isolator located between the electrodes. The isolator is constructed as a light guide. By light guides is meant in the following also optical waveguides which are suitable for components of the spectrum other than visible components. In this respect, it is advantageous to connect the light guides in an optically active manner with a light generating unit. This light generating unit can be a suitable lamp, e.g., a halogen lamp, as well as a laser. The radiation is advantageously coupled into the light guide by suitable optical systems, e.g., lenses or optical gratings, known to the person skilled in the art. According to the invention, the light guide can also comprise a bundle of light-conducting fibers. The electrodes have corresponding contacts for connecting to a power supply unit. It is particularly advantageous when the light guide comprises a flexible light guide which is constructed continuously from the probe tip to the light generating unit. Alternatively, the invention can also be realized in that the probe is constructed as a separable unit which is connected with the light generating unit via a flexible light guide with corresponding coupling points.
The light can be conducted in the light guide by the principle of total reflection. Alternatively, it may also be favorable to provide the jacket surfaces of the light guide with a reflective coating.
It has proven advantageous when the electrodes do not closely contact the insulator, but rather have a clearance of several hundredths of a millimeter. This increases the flexibility of the light guide; moreover, it has been shown that there is less light loss as a result of this step.
In realizing the invention, it has turned out that the probe according to the invention can also be used advantageously in other areas of technology. Its use is particularly advantageous when the measurements or treatments to be carried out require the combination of optical and electrical methods. For example, in cell biology, electric potentials or changes in potential are measured directly at the location of optical stimulation. For this purpose, light of suitable intensity, wavelength and/or signal duration is directed via the light guide to the relevant location on the specimen and simultaneously or subsequently detects a possible change in potential by means of the electrodes using measurement techniques. It is likewise possible to carry out electrical and optical stimulation simultaneously or with a delay in time in that the electrodes are acted upon by voltage and corresponding light pulses are directed via the light guide to the active point of the electrodes or into the vicinity thereof.